On Thu, 8 Oct 2009, Oliver Neukum wrote: > Am Donnerstag, 8. Oktober 2009 22:06:10 schrieb Alan Stern: > > > > > On further thought, unthrottle should autoresume if the device is > > open and autosuspended (but it shouldn't do anything if the device is > > suspended). After all, the reason for the autosuspend may have been > > the lack of activity caused by the throttling. > > > > In practice this isn't likely to come up. It would be surprising if > > throttling lasted long enough to cause an autosuspend or if the core > > decided to throttle while the device was autosuspended and hence idle. > > So you say that throttle() should do an autopm_put? The way you've coded the sierra and option drivers, it's not necessary. Those drivers do an autopm_get_async during submission and an autopm_put_async after the completion of every output URB (and they update the last_busy time in the completion of every input URB). When the driver is throttled no URBs will be submitted, so the usage count will remain at 0 with no effort on the part of throttle(). For other drivers that use the simpler "autoresume on tty install, autosuspend on tty cleanup" approach provided by usb-serial.c, the throttle routines obviously don't need to worry about runtime PM. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
